Eyes may be windows to spot Alzheimer’s disease

Washington – A team of researchers has found that the loss of a particular layer of retinal cells not previously investigated may reveal the presence of Alzheimer’s disease and provided a new way to track the progression of the disease.

The researchers, from Georgetown University Medical Center (GUMC) and the University of Hong Kong, examined retinas from the eyes of mice genetically engineered to develop Alzheimer’s disease (AD).

“The retina is an extension of the brain so it makes sense to see if the same pathologic processes found in an Alzheimer’s brain are also found in the eye,” R. Scott Turner, MD, PhD, director of the Memory Disorders Program at GUMC and the only U.S. author on the study said. “We know there’s an association between glaucoma and Alzheimer’s in that both are characterized by loss of neurons, but the mechanisms are not clear.”

In their study, the researchers looked at the thickness of the retina, including the inner nuclear layer (not previously study in this setting) and the retinal ganglion cell layer.

They found a significant loss of thickness in both. The inner nuclear layer had a 37 percent loss of neurons and the retinal ganglion cell layer a 49 percent loss, compared with healthy, age-matched control mice.

In humans, the structure and thickness of the retina can be readily measured using optical coherence tomography. Turner says this new tool is increasing finding applications in research and clinical care.

Turner said that the study suggested another path forward in understanding the disease process and could lead to new ways to diagnose or predict Alzheimer’s that could be as simple as looking into the eyes.

The study was presented at Neuroscience 2013.